import java.util.Scanner;
public class Book38_8{
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		System.out.printf("请输入:");
		double a,b,c,s;
		a = input.nextDouble();
		b = input.nextDouble();
		c = input.nextDouble();
		s = (-b+Math.sqrt(b*b-4*a*c))/(2*a);
		System.out.println("结果为：" + s);
	}
}